title: Manipulation of estrogen synthesis alters MIR202* expression in embryonic chicken gonads.
abstract: Tissue-specific patterns of microRNA (miRNA) expression contribute to organogenesis during embryonic development. Using the embryonic chicken gonads as a model for vertebrate gonadogenesis, we previously reported that miRNAs are expressed in a sexually dimorphic manner during gonadal sex differentiation. Being male biased, we hypothesised that up-regulation of microRNA 202* (MIR202*) is characteristic of testicular differentiation. To address this hypothesis, we used estrogen modulation to induce gonadal sex reversal in embryonic chicken gonads and analyzed changes in MIR202* expression. In ovo injection of estradiol-17beta at Embryonic Day 4.5 (E4.5) caused feminization of male gonads at E9.5 and reduced MIR202* expression to female levels. Female gonads treated at E3.5 with an aromatase inhibitor, which blocks estrogen synthesis, were masculinized by E9.5, and MIR202* expression was increased. Reduced MIR202* expression correlated with reduced expression of the testis-associated genes DMRT1 and SOX9, and up-regulation of ovary-associated genes FOXL2 and CYP19A1 (aromatase). Increased MIR202* expression correlated with down-regulation of FOXL2 and aromatase and up-regulation of DMRT1 and SOX9. These results confirm that up-regulation of MIR202* coincides with testicular differentiation in embryonic chicken gonads.
authors.affiliation: CSIRO Livestock Industries, Australian Animal Health Laboratory, Geelong, Victoria, Australia. stephanie.bannister@univie.ac.at
authors.forename: Stephanie C
authors.initials: SC
authors.lastname: Bannister
authors.forename: Craig A
authors.initials: CA
authors.lastname: Smith
authors.forename: Kelly N
authors.initials: KN
authors.lastname: Roeszler
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Doran
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Sinclair
authors.forename: Mark L V
authors.initials: ML
authors.lastname: Tizard
mesh_terms: D000818:Animals; D002642:Chick Embryo; D004967:Estrogens / Q000096:biosynthesis*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006066:Gonads / Q000378:metabolism*; D008297:Male; D035683:MicroRNAs / Q000378:metabolism*; D012733:Sex Differentiation; D015854:Up-Regulation
chemical_list: D004967:Estrogens; D035683:MicroRNAs